[FFmpeg-devel] [PATCH] lavfi/af_sofalizer: remove exp2 and replace clz by ff_clz

[Ganesh Ajjanagadde]

On Fri, Jan 1, 2016 at 11:08 AM, Paul B Mahol <onemda at gmail.com> wrote:
> On 1/1/16, Ganesh Ajjanagadde <gajjanagadde at gmail.com> wrote:
>> On Tue, Dec 29, 2015 at 1:17 PM, Ganesh Ajjanagadde
>> <gajjanagadde at gmail.com> wrote:
>>> ff_clz is faster, and uses an intrinsic (at the moment on GCC). exp2 is
>>> a wasteful function for a simple integer exponentiation.
>>>
>>> Untested.
>>>
>>> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
>>> ---
>>>  libavfilter/af_sofalizer.c | 5 +++--
>>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/libavfilter/af_sofalizer.c b/libavfilter/af_sofalizer.c
>>> index 6a24cbc..0bd1931 100644
>>> --- a/libavfilter/af_sofalizer.c
>>> +++ b/libavfilter/af_sofalizer.c
>>> @@ -30,6 +30,7 @@
>>>
>>>  #include "libavcodec/avfft.h"
>>>  #include "libavutil/float_dsp.h"
>>> +#include "libavutil/intmath.h"
>>>  #include "libavutil/opt.h"
>>>  #include "avfilter.h"
>>>  #include "internal.h"
>>> @@ -996,8 +997,8 @@ static int config_input(AVFilterLink *inlink)
>>>      }
>>>      /* buffer length is longest IR plus max. delay -> next power of 2
>>>         (32 - count leading zeros gives required exponent)  */
>>> -    s->buffer_length = exp2(32 - clz((uint32_t)n_max));
>>> -    s->n_fft         = exp2(32 - clz((uint32_t)(n_max +
>>> inlink->sample_rate)));
>>> +    s->buffer_length = 1 << (32 - ff_clz(n_max));
>>> +    s->n_fft         = 1 << (32 - ff_clz(n_max + inlink->sample_rate));
>>>
>>>      if (s->type == FREQUENCY_DOMAIN) {
>>>          av_fft_end(s->fft[0]);
>>> --
>>> 2.6.4
>>>
>>
>> ping
>
> OK if you remove dead code, clz() function.

Done, pushed, thanks.

>
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